Python

# List and List's method

# Review Variable

img

  • As you might see the variable can contain only one data. However, what if we want to contain more than one?

  • not a good example

a0 = 3
a1 = 23
a2 = 5
a3 = "Hello"
1
2
3
4

# Using List

img

a = [3, 23, 5, "Hello"]
1

# Getting

a = [3, 23, 5, "Hello"]
print(a[0])
print(a[1])
print(a[2])
print(a[3])
print(a[4]) # ??
1
2
3
4
5
6

# Setting

a = [3, 23, 5, "Hello"]

a[3] = "HelloWorld"
a[1] = a[0] + a[2]
print(a)
1
2
3
4
5
output

OUTPUT

[3, 8, 5, 'HelloWorld']

# List's method

# len

a = [3, 23, 5, "Hello"]

count = len(a)
print(count)
1
2
3
4
output

OUTPUT

4

# in

a = [3, 23, 5, "Hello"]

bool1 = 23 in a
bool2 = 50 in a
print(bool1)
print(bool2)
1
2
3
4
5
6
output

OUTPUT

True
False

# append

a = [3, 23, 5, "Hello"]
a.append(20)
print(a)
1
2
3
output

OUTPUT

[3, 23, 5, 'Hello', 20]

# del

a = [3, 23, 5, "Hello"]
del a[2]
print(a)
1
2
3
output

OUTPUT

[3, 23, 'Hello']

# remove

a = [3, 23, 5, "Hello"]
a.remove("Hello")
print(a)
1
2
3
output

OUTPUT

[3, 23, 5]

# index

a = [3, 23, 5, "Hello"]
where_is_hello = a.index("Hello")
print(where_is_hello)
1
2
3
output

OUTPUT

3

# Let's start coding together

  • To be given score. Then show the grade. (use only array, can't use if)
Grade Score
A [80, 100]
B [70, 80)
C [60, 70)
D [50, 60)
F [0, 50)

OUTPUT

score: 99
get A

OUTPUT

score: 50
get D

OUTPUT

score: 72
get B

OUTPUT

score: 49
get F
Solution 
score=float(input("score : "))
i=int(score//10)
g=["F","F","F","F","F","D","C","B","A","A","A"]
print(f"get {g[i]}")
1
2
3
4

# Exercise Book 10.List